The commonly seen pneumatic tool aims to provide a driving force through a pneumatic motor to rotate a spindle and drive a grinding member coupled on a distal end of the spindle to perform surface grinding operation. Refer to FIG. 1 for a conventional grinding member 10 which is coupled with a fastening element 11 in an integrated manner. The fastening element 11 has a screw thread 12 on a distal end to be fastened to a coupling head 22 of a pneumatic tool 20.
As the grinding member 10 and the fastening element 11 are fabricated in an integrated manner, when the grinding member 10 has been used for a period of time and has to be replaced, the fastening element 11 also is discarded. This results in an extra cost.
Moreover, the grinding member 10 is fastened to the coupling head 22 of the pneumatic tool 20 merely by the fastening element 11. The grinding member 10 is prone to deform when being rotated at high speed.